Ok,
Theoretically I have covered both since my dns has the cname "wpad" redirecting 
to my webserver which dishes out wpad.dat from its root and my dhcp server has 
option 252 referencing that complete url.:)
My wpad file looks similar to yours as well.

I see some issues searching the net on ie7 though, I just found that the GPO 
setting for it is rather flaky, sigh...

Thanks!
jlc

-----Original Message-----
From: Ben Scott [mailto:[email protected]] 
Sent: Thursday, January 08, 2009 3:37 PM
To: NT System Admin Issues
Subject: Re: WPAD Proxy Config

On Thu, Jan 8, 2009 at 4:45 PM, Joseph L. Casale
<[email protected]> wrote:
> Well, my firefox clients pick up the settings but not ie7.
> I am using the dns (cname) / dhcp option 252 method.
>
> How are you doing it, and do you have it working with ie7?

  We haven't deployed MSIE 7 here yet.  I'll see if I can get a
sandbox VM running with it to test.  MSIE 6 and Firefox 3.x on Win XP
Pro SP2 both work fine.

  Here's what we did:

  We implemented the DNS method of WPAD.  We didn't even bother with
DHCP; the DNS method has worked fine for us for everything.  I seem to
recall reading that the DHCP method isn't as widely implemented in
clients, but I could be wrong on that.

  We created a CNAME record named <wpad.corp.example.com.>, where
<corp.example.com.> is our Active Directory domain name, and the
default DNS suffix for our LAN.  Thus, clients attempting to do WPAD
via DNS end up requesting <http://wpad.corp.example.com/wpad.dat>.
The right-hand-side of the CNAME record specifies
<foo.corp.example.com.>, where <foo> is our proxy server.

  Our proxy server also runs an Apache web server, which is configured
with an alias such that </wpad.dat> redirects to </proxy.pac>.  That's
our proxy auto-config script.  Apache also knows that a *.pac file is
of MIME type <application/x-ns-proxy-autoconfig>.  To do that, the
following was added to the Apache config file:

        AddType application/x-ns-proxy-autoconfig .pac
        Redirect /wpad.dat http://foo/proxy.pac

  Our proxy auto-config script looks like this:

        function FindProxyForURL(url, host) {
                if (    isPlainHostName(host)
                        || dnsDomainIs(host, ".corp.example.com")
                        || shExpMatch(url, "http://10.*";)
                        || shExpMatch(url, "http://127.*";)
                )
                        return "DIRECT";
                else
                        return "PROXY proxy:8080";
        }

  We also have a CNAME <proxy.corp.example.com.> that yields our proxy
server.  (I'm big on using generic aliases for specific hosts, so when
things change you don't have to reconfigure a bunch of things, just
the alias.)  The script causes browsers to bypass our proxy for
internal systems, and use our proxy for everything else.

-- Ben

~ Finally, powerful endpoint security that ISN'T a resource hog! ~
~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/>  ~

~ Finally, powerful endpoint security that ISN'T a resource hog! ~
~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/>  ~

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